Liquid pressure amplifiers such as injectors and hydrokinetic amplifiers often require a start-up overflow. They receive liquid and vapor which they combine into a pressure amplified output liquid; but to achieve maximum pressure amplification, they require a brief overflow during start-up. After start-up, the overflow line is often subject to subatmospheric pressure and so includes a check valve oriented to block inflow.
Liquid pressure amplifiers can be arranged to receive continuously available liquid and vapor inputs and yet deliver output pressure intermittently via a delivery valve that can open and close on demand. A common example of this is a high pressure washing gun powered by a liquid pressure amplifier and having a delivery trigger operated to be on or off. When such a delivery valve temporarily closes, the amplifier cannot deliver output pressure and stops operating. The input liquid and vapor continue to flow, however, and pour out the overflow line, wasting both liquid and energy. When the delivery valve reopens, the amplifier restarts, which stops the overflow.
I have discovered a way of checking the overflow whenever it is not required for start-up. This includes blocking any overflow that occurs while a liquid pressure amplifier is operating and also blocking overflow of liquid and vapor inputs when a closed output line prevents the amplifier from operating. My arrangement limits overflow to a negligible amount that occurs only during an actual startup, and my system otherwise contains all the liquid and vapor except that volume deliberately delivered as pressurized liquid output. My invention thus reduces waste and improves the efficiency of a liquid pressure amplifier while allowing it a start-up overflow that is necessary for maximum pressure amplification.